Patients receive first custom-made bladders
WASHINGTON – Custom-made bladders grown from patients’ own cells have been successfully transplanted and work, in some cases for years, scientists reported.
Writing in a special report in the Lancet medical journal, they described the cases of seven patients who had new bladders engineered from a plug of tissue grown from their own, dysfunctional bladders.
“We have shown that regenerative medicine techniques can be used to generate functional bladders that are durable,” said Dr. Anthony Atala of Wake Forest University in North Carolina, who led the research.
“This suggests that regenerative medicine may one day be a solution to the shortage of donor organs in this country for those needing transplants.”
Patients given transplants of bladders made from their own cells would not need to take drugs to prevent organ rejection, as do patients given transplants from either living or dead donors.
Atala’s team worked with immature cells known as progenitor cells from the patients’ bladders. They have been working for 16 years to find ways to first identify and separate these cells, then to coax them into growing on a scaffold into the two main cell types found in bladders.
The patients were children and teens aged 4 to 19 who had poor bladder function because of a congenital birth defect that causes incomplete closure of the spine.
Their bladders are too stiff and can cause pressure on the kidneys that eventually damages them. Such patients often get bladders reconstructed from the intestines, but the procedure is imperfect.
Atala, a urinary surgeon and an expert in regenerative and stem cell science, wanted to try to grow replacement bladders for the patients.
MEASURING FOR A MATCH
“We do a three-dimensional CT scan, a computerized imaging analysis, and we figure out what the bladder shape should look like,” Atala said in a telephone interview. “We then take a small biopsy of their bladder, about half the size of a postage stamp.”
They separate the muscle cells on the outside of the bladder, and the specialized cells that line the baglike organ.
Then they create an artificial scaffold on which to layer the cells. The cells are grown in special compounds that nurture the progenitor cells and allow unwanted cells to die out.
The resulting cells are then layered onto the scaffold and incubated until they grow and spread.
“It is very much like baking a layer cake,” Atala said. “You are placing these cells on one layer at a time.”
Atala works with stem cells, the body’s master cells, but in this case, his team made use of progenitor cells, which are slightly further along the pathway from a “blank slate” master cell.
His team is also working to create blood vessels, kidneys, pancreases, hearts, livers and nerves.
The technology has been licensed from Atala’s former employer, Children’s Hospital in Boston, to a new company called Tengion created to take advantage of Atala’s work.
“Tengion raised $39 million in an a round of venture capital,” Gary Sender, chief financial officer of the company, said in a telephone interview.
Sender said Tengion would seek Food and Drug Administration approval for clinical trials of the new bladders later this year. The agency would have to review the bladder as a device and as a biological product, he said.